1. Technical Field
The present invention relates generally to wireless communication systems; and more particularly to a wireless communication system in which a call is received by a mobile switching center from a private branch exchange for a mobile unit and in which the call is selectively routed to the mobile unit and, when the call is routed to the mobile unit, a distinctive alert signal is provided for the call.
2. Related Art
Cellular wireless communication systems are generally known in the art to facilitate wireless communications within respective service coverage areas. Such wireless communication systems include a xe2x80x9cnetwork infrastructurexe2x80x9d that facilitates the wireless communications with mobile units operating within a service coverage area. The network infrastructure typically includes a plurality of base stations dispersed throughout the service coverage area, each of which supports wireless communications within a respective cell (or set of sectors). The base stations couple to base station controllers (BSCs), with each BSC serving a plurality of base stations. Each BSC couples to a mobile switching center (MSC) which also couples to the PSTN, the Internet and/or to other MSCs.
A wireless mobile unit operating within the service coverage area communicates with one or more of the base stations. The base stations route the communications to the MSC via a serving BSC. The MSC routes the communications to another subscribing wireless unit via a BSC/base station path (which may be the same BSC/base station path when the communications are with another subscribing unit serviced by the same base station) or via the PSTN/Internet/other network to terminating destination.
Various operating standards have been developed to standardize wireless communications. The wireless communication operating standards include, for example, the Advanced Mobile Phone Service (AMPS) standards, the Global Standards for Mobility (GSM), the Code Division Multiple Access (CDMA) and the Time Division Multiple Access (TDMA) standards. A standard that is employed in North America for interconnectivity of MSCs is the IS-41 standard. These operating standards set forth the technical requirements that facilitate compatible operation between equipment of differing vendors.
Mobile units are used for many differing applications. In many applications, they simply serve as telephones for their users. However, in other applications, they take the place of two-way radios. A particular example of such usage is when mobile units are provided to delivery or service personnel. The mobile units are used primarily for communication between a central office and the delivery or service personnel during normal working hours when the delivery or service personnel are in the field. When the mobile units are used for this purpose, however, problems may arise. For example, one problem arises when a service person is in the middle of a job and a call is incoming. The service person must cease his or her immediate activity to answer the phone. Valuable time is lost in answering phone calls that do not relate to the work performed by the service person. Another problem relates to the service personnel receiving unnecessary phone calls on his or her mobile unit. Since the mobile unit is provided by the employer, the employer may desire that the service person not receive calls from outside parties.
Thus, there is a need in the art for a wireless communication system in which calls to delivery or service personnel may be managed by a wireless communication system.
Thus, to overcome the shortcomings of the prior systems, among other shortcomings, a wireless communication system constructed according to the present invention determines whether an incoming call intended for a serviced mobile unit originated from a private branch exchange. In one operation, if the call originated from the private branch exchange, a distinctive ringing signal is used to alert the user of the mobile unit while calls originating from a non-private branch exchange source are terminated with a normal ringing cadence. In another operation, only calls that originate at the private branch exchange are completed to the mobile unit.
A wireless communication system constructed according to the present invention includes an originating mobile switching center (MSC), a home location register (HLR), a serving MSC and supporting infrastructure for each MSC. Such supporting infrastructure includes a plurality of base station controllers (BSC) and a plurality of base stations. The base stations support wireless communications within respective cells to service mobile units operating in the cells.
When a call is received by the originating MSC intended for the mobile unit, the originating MSC determines whether the call originated from a private branch exchange. Such determination is made based upon whether the call was incoming on a designated trunk line or from a caller ID assigned to the private branch exchange.
If the call originated from the private branch exchange, the call is competed and a distinctive ringing is provided to the mobile unit to indicate that the call originated at the private branch exchange. In such case, a user of the mobile unit, such as a delivery or service person may ignore calls that did not originate from the private branch exchange and receive calls that did originate from the private branch exchange. Calls that did not originate from a private branch exchange are completed normally.
Alternatively, only calls that originated at the private branch exchange are completed to the mobile unit. In determining whether to route calls to the mobile unit, the HLR may investigate the subscriber preferences for the mobile unit. By routing only those calls that originated at the private branch exchange, a delivery or service person will not receive calls on the mobile unit from other callers.